Amazon could have another winner with its Buy with Prime service, according to Morgan Stanley. The company started out as an online bookseller, morphed into an e-commerce giant and tackled cloud computing with Amazon Web Services. Its newest program, Buy with Prime , allows Prime members who purchase from another retailer’s website to check out using their Amazon account and receive free, two-day delivery. The service could rake in billions for Amazon , analyst Brian Nowak said. AMZN YTD mountain Amazon’s year-to-date performance Every 2% of non-Amazon.com packages that shift to Buy with Prime would add $5.9 billion to Amazon’s 2025 revenue and $1 billion to annual earnings before interest and taxes (EBIT), he estimated in a note Tuesday. His bull case of 5% of non-Amazon volume translates to $3.5 billion of annual EBIT. Amazon’s new service competes directly with Shopify, which warned its merchants in September that those who use Buy with Prime will violate Shopify’s terms of service. Nowak said Amazon has an edge. “Buy with Prime shipping is priced competitively vs peers while also offering the fastest delivery,” he said. “Pricing between AMZN and SHOP is at rough parity (~$8 to ship each package)…though AMZN offers 1-2 day shipping vs SHOP at 2-3 day.” The other option is for buyers to coordinate their own shipping through delivery services such as UPS and FedEx, which is more expensive, Nowak added. Amazon reports quarterly earnings on Thursday. Its shares are up more than 21% this year. — CNBC’s Michael Bloom contributed reporting.